This invention relates to internal combustion engines of the four and two stroke convertible reciprocating type wherein the thermal cycle is totally optimized in connection with: the integrated gas distribution intake and exhaust valve system, the combustion process, constant specific fuel consumption, variable geometry combustion chamber, variable compression ratio, automatic constant combustion pressure, variable expansion ratio, variable displacement capacity, and variable load and speed adjustment, all associated with a regenerative, internal thermal process (without cooling), and a very low friction mechanism (without hot lubricated surfaces). All these conditions are optimized and controlled by a central microprocessor associated with the engine.
The state-of-the-art engines (in production) utilize a conventional poppet valve system for intake and exhaust gas flows, in both spark ignition and diesel applications. This valve system has evolved after continuous development for over 80 years in the conventional overhead-valve configuration. These valves are actuated by cam operated push tubes (cam followers) and linkage systems or directly by the cams. The valve timing is fixed and is usually optimized for good breathing at the Design Point. The conventional valve systems are specific for two or four stroke engines, without the ability to change the type (to convert) of engine to use either cycles depending upon the power requirement.
Disadvantages of current poppet valves include:
(a) Porting area limited by cylinder bore size PA1 (b) Crowding of the cylinder head (configuration). PA1 (c) Valve overlap with limited scavenging. PA1 (d) High thermal stress of the exhaust valves. PA1 (e) Hot surfaces for gasoline engines limiting the antidetonation capacity of the combustion chamber. PA1 in one configuration the poppet valve is concentric with a group of double-sliding cam profiles an a rotary valve shaft, which act through a cam follower and a rocker-arm of the poppet valve, for both the convertible two and four stroke cycles; PA1 in another configuration the poppet valve is concentric with a single cam profile and the rotary valve shaft, acting through a cam follower and a rocker arm of the poppet valve exclusively for either the two or four stroke cycles. PA1 the discontinuous variation is associated with a specific compression ratio, and PA1 the continuous variation is associated with a variable compression ratio and a constant peak pressure of the cycle.
The combustion process in the conventional combustion chamber with constant volume is optimized with the operational design point in relation to a fixed compression ratio, fixed expansion ratio and a constant volumetric capacity (displacement). These parameters provide a compromise solution for each specific engine in relation with the application. The detonation limit of the homogenous fuel-air mixture from the carburator and the effectiveness of the spark ignitors are the major barriers against the evolution of the gasoline engine. These factors limit the compression ratio and the supercharging level. The same situation holds for the gas engine, fueled by natural gases, in which the detonation (octane limit) of the engine is in fact the limit of the general performance and results in an extremely low efficiency.
The cooling system, associated with the lubrication requirement of the hot surfaces which have high friction components (pistons, rings, etc.) is a major source of heat loss.
All these factors limit the evolution of the thermal engines and are characteristic of the actual state-of-the-art for all types of engines, either for spark ignition or compression ignition.
This invention relates to a complex of integrated solutions correlated in an optimized energetic system in which: the gas distribution system for intake and exhaust is able to perform in both the two cycle and four cycle convertible modes or in a fixed mode for either cycle.
The mechanical distribution system is composed generally of an integrated system in which:
In another configuration, the poppet valve is concentric with a single-frontal cam profile in a common body with the pusher which acts up-and-down on the poppet valve, combining both a rotary and translatory movement for both the two or four stroke cycle.
All these configurations are associated with variable geometry intake and exhaust ports and channels located in the cylinder head and variable geometry scavenging ports located at the bottom dead point of the cylinder liner. The variation of the ports and the timing are governed by electromagnetic actuators under the control of a programmed microprocessor.
Attached to the common shaft is a magnetic disc supporting the magnetic code associated with the time base of the rotation. This is the source of the signals transmitted to the microprocessor which in turn command the actuators.
The hydroelectric gas distribution system is composed of an integrated hydraulic-piston-poppet valve concentric with a common hydraulic rotary cylinder and a rotary gas valve. These are associated with variable geometry intake and exhaust ports and channels located in the cylinder head and variable geometry scavenging ports located at the bottom dead point of the cylinder liner. The phase correlation and timing of the circulation of the hydraulic working fluid are controlled by a set of electro-magnetic valves and actuators controlled by an optimized microprocessor. The rotating movement of the hydraulic cylinder and rotary valve is activated by the crankshaft in the specific ratios of 1/1 for two stroke and 1/2 for the four stroke cycle.
The combustion process takes place in the variable geometry combustion chamber in which the volume ratio and the connection between the working spaces are optimized in relation with the energetic process in which:
A different combustion chamber that has a specific variation of the entire geometry of the precombustion chamber is provided with a central sliding profile and produces a differential variation of the compression process in the precombustion chamber. A restrictive and variable connection passage that permits a high compression ratio in the cylinder for the air and a low compression ratio variation before combustion for the mixture (fuel and air) or simple gas is provided. A high turbulence level is maintained in the precombustion chamber at all rotation and piston speeds. Also, an antidetonation conditioner is provided which raises the connection surface passage in the time of ignition, combustion, expansion and exhaust reducing the gaso-dynamic losses. During this process the premixture is prevented from achieving a detonation condition. Also, the compression of the pure air separately from the rich mixture of fuel eliminates all the restrictions for compression and supercharging levels and any restrictions on the octane number of the fuel.
Related to this process is the fact that the compressed air is injected into the premixed fuel. This is exactly inverse in comparison with the diesel process in which the fuel is injected into the compressed air, and totally different from the Otto process in which the mixture between the fuel and air is constant. Based on the fact that the restrictive (reduced) connection section can be specifically adjusted for each rotation level, the optimized level of the turbulence can be maintained for all levels of rotation. This process produces the best mixture formation for all the possible operating regimes. The central piston with a variable profile is under the dual control of an adjustable spring which is associated with a hydraulic computerized system that provides the time of restriction and the position of the profile in relation with all phases of the cycle. During the restriction time coincident with the compression stroke, the variation of the compression pressure in the precombustion chamber is far smaller than the variation of the compression in the cylinder. During this restriction time, the new charge of gaseous fuel or gasoline rich air-mixture is injected into the precombustion chamber at a relatively low pressure, is heated, mixed and accelerated in a toroidal manner combined with a high turbulence level by the compressed air admitted through the restrictive variable channel connected to the cylinder.
The optimized variation of the combustion chamber volume is correlated with the optimized distribution phases. This process controls the quantity of air and the initial volume at the beginning of the compressor stroke.
The optimized variation of the-active volume of the cylinders (after the intake closing) is correlated with: the energetic regime, the variation of numbers of cycles (two or four stroke), the variation of the active number of cylinders, the continuous variation of the compression ratio, and the continuous variation of the expansion ratio. All these factors are the base of a total optimized thermal energetic system integrated in an internal combustion engine utilizing a programed microprocessor system.
The thermodynamic cycle of the engine is characterized by a variable compression stroke associated with an elongated expansion stroke. This process dramatically improves the efficiency of the engine at all loads and operating speeds.
In the energetic process of this internal combustion engine, utilizing a regenerative internal cycle, the cylinder walls and all the hot surfaces of the combustion chambers are made from regenerative cells in which the compressed air is cyclically infiltrated as in an insulating substance.
The cyclic process (the intake, compression expansion, exhaust and scavenging specific to the thermal piston engine) is the base of the continuous movement of the compressed air and provides the real INTERNAL RECOVERY of the energy equivalent to the cooling process in the normal diesel engine.
The regenerative thermal process, with the continuous exchange of the air to the inside and outside of the cells (especially the external radial movement of the air in the expansion stroke toward the cylinder space) produces a dynamic separation of the hot gases from the cylinder walls. This action produces a supplimentary dynamic air shield insulation, centralizing the hot combustion gases in the cylinder in a real adiabatic barrier between the hot sources (combustion gases) and the cylinder walls (regenerative cells).
The same strong radial movement of the high density air from the regenerative cells toward the central cylinder space eliminates the depositing of the carbon particulates on the walls of the regenerator, constituting a continuous air cleaning system.
The expansion stroke and the radial movement of the fresh compressed air accumulated in the regenerative cells, amplify the turbulence and supply preheated air for the final process of the combustion. This process reduces all the carbon, cleans the combustion process and eliminates the pollution problems associated with current state-of-the-art engines.
Also, the piston and the regenerative cells constitute an active sealing system in simulating a staggered labyrinth which provides a high quality sealing process.
The piston and the hot surfaces of the regenerative cells are not in contact and thus require no lubrication. The side thrust of the piston against the cylinder walls is supported by the internal zone of the metallic cylinder (like a crosshead) in which the low temperatures and lubrication are not effected.
The regenerative thermal engine may function in a combined cycle to produce an internal congeneration of power and superheated steam which is produced from the excess energy (waste heat) from the reciprocating internal-combustion engine.
The regenerative thermal engine with its internal combustion and steam generation makes a unique machine and its separate thermal cycles (gases and steam) develop themselves simultaneously in parallel, recuperatively, compensatorily and integratedly. The working agent is made up from the active phases (expansion and exhaust) of the burned gases of the internal-combustion engine and of the superheated steam, generated from the integrated recuperative regenerator. This homogenious mixture acts on the piston and expands through a turbine (if used on a supercharged-engine).
The residual energy of the internal-combustion engine is transferred to the Rankine cycle of the integrated steam generator by a complex heat transfer process (conduction, convection, radiation, contact and mixing) which takes place through the walls of the cylinders of the internal combustion engine. The heat energy in the cooling fluid then is radially injected into the regenerative cells (from outside to inside). The cooling fluid then passes through the stages of preheating, vaporization and superheating and finally injected simultaneously with the fuel into the inner cylinder cooling jacket. It then proceeds to a chamber, concentric with the combustion chamber, where simultaneously takes place the fuel combustion and the process of vaporization with the final superheating of the steam. The mixing of the two working agents and the expansion in the cylinder of the thermal reciprocating engine continued through the expansion of gases and steam in the turbine allow the complete utilization of the thermal energy (of the gases and the steam). The working agents expand completely, close to the condensation state of the steam, which process takes place in the noise-absorber of the condenser. This concludes the thermal passage route of the working fluid. The recovered water in the condenser (preferably at 80-90 degrees C.) is introduced again into the thermal cycle of the integrated thermal engine with an increased quantity of the condensated steam resulting from the hydrocarbon combustion. The system of the integrated regenerative thermal cycle, which carries and recuperates all the thermal energy generated in the engine cylinder from outside to inside automatically, creates an adiabatic state, eliminating the thermal loss and leads to the elimination of the cooling system (except for the supercharged air).